/**
 * Append-only record of what each send actually achieved, written after the
 * \Sent read-back has returned.
 *
 * This is deliberately not an intent line. "Filed to Sent" written before the
 * read-back would be the same unverified claim the model was already making,
 * relocated into a log where it is harder to challenge (Task 1822). Every row
 * here states an observed outcome.
 *
 * It exists because nothing else records that a send happened at all — SMTP
 * diags only on failure — so the standing sweep had no left-hand side to
 * reconcile \Sent against.
 */
export interface SentLedgerEntry {
    at: string;
    accountId: string;
    mailbox: string;
    messageId: string;
    copy: "found" | "not-in-sent" | "no-sent-folder" | "check-failed";
    sentFolder?: string;
    sentUid?: number;
}
export declare function ledgerPath(): string;
/**
 * Append one row. Pure append, never read-modify-write.
 *
 * Two sends completing together would otherwise interleave read/read/write/
 * write and silently drop a row, which would show up later as a phantom
 * shortfall. O_APPEND keeps concurrent single-line writes from tearing.
 * Trimming is the sweep's job — see pruneSentLedger.
 */
export declare function appendSentLedger(entry: SentLedgerEntry): void;
/**
 * Drop rows past the retention window.
 *
 * Called once per sweep run, from the sweep's own single process, rather than
 * on every send: rewriting the file is the one operation that can lose a
 * concurrent append, so it happens as rarely as possible and never on the send
 * path. A send landing inside the rewrite window loses at most its own
 * observability row, never the mail.
 */
export declare function pruneSentLedger(): void;
export declare function readSentLedger(sinceMs: number): SentLedgerEntry[];
//# sourceMappingURL=sent-ledger.d.ts.map